Dominox Propane Torch Head Repair.

 

    I got this on Amazon, coming on a year ago, right around the time that I was heavily invested in getting my car back on the road, after a timing chain slip.  As an earlier post here testifies, right about when I had all of the heavy lifting done, I stupidly destroyed the auxiliary belt tensioner.   I managed to get a secondhand replacement on eBay, but figured, as a penance, I'd also try repairing the broken one.

    Hence, the torch head purchase, as well as a tube of aluminium welding rods, also from Amazon.  That was also as far as I got, repair-wise - after all, the car was fixed, which was all the incentive I needed to do nothing!

    But it turned out that the torch I had bought for the job, needed a fix as well, specifically, the igniter didn't work.  I posted the below video as part of my review on Amazon, highlighting the problem.  Prior to purchase, I had noted on Amazon's reviews, that this was a reoccurring problem.  I was also aware that it was a Chinese copy of a 'Western-branded' torch - therefore about a quarter of the cost - so worth the gamble...

 

    ...but which didn't pay off!  So, there it lay for a year, until a day or so ago, when I finally had a look at it.  It may have been cheap, but it's a very nice (copy of the original) design.  The 'fix' was surprisingly easy, whomever assembled the unit was to blame - they neglected to thread the igniter-wire through the 'retaining spring', which keeps it centered in the torch barrel, preventing the ignition spark from shorting to ground.  Once done, the igniter works perfectly - no doubt as well as the torch costing 4 times the price, I'd wager!

    The Igniter's re-assembly sequence can be seen in the below pics.

Dominox Torch

 

Igniter assembly sequence

Igniter-wire centered

Igniter-wire displaced

   

 

Mastech HY3005F-3 Bench Power Supply Repair.

    Over the last two decades, I must have acquired at least a couple of thousand Euros worth of electronics test equipment.  Collecting test equipment, most like-minded individuals would consider understandable, after all, who doesn't like tinkering.  But measuring equipment without components to measure stuff off of, is of no use to a tinkerer, so add to that a few thousand more Euros worth of components to the bill of acquired goodies - while knowing all the while that 99% of them I will never use!  But, as the saying goes, "possession is nine-tenths of the law", and I'd rather possess, when the possession is needed - never mind that most of the unused possessions will eventually end up in a skip at some time in the future.

    Case in point, is the Mastech Bench PSU.  This was bought 10-15 years ago as a replacement, after I had smoked a beloved, though less-capable supply, with high voltage, and that I had 'liberated' from an employer in the distant past.  The Mastech performed well for years.  After a while, I would notice that the displayed voltage would fluctuate a bit, but no biggie.  Over a year or two, that observance became an irritant, then quickly became an annoyance, the voltage jitter increasing in lockstep to my temperament.  I remember at the time, trawling through Reddit, searching for a solution.  On the plus side, I learned that the Mastech - one of a handful of names that it was known by - all in all, was seen by most, as fairly reliable.  Jittery voltage displays was noted however, along with the consensus that either reservoir electrolytics or the voltage pots, needed replacing.

    In my head, I poo-poo'ed the potentiometer solution, mainly because on my PSU, both supplies fluctuated badly, despite, by my reckoning, the right-hand side having been the main work-horse, the left having had sparse usage.  So caps it was, I decided, and promptly ordered some.  But, as an afterthought, I added a bag of assorted pots to the BOM, just in case...

    And there both lay, gathering dust, for the best part of two years - enough time, that I had even forgotten about having ordered the pots!  By this time, the voltage fluctuations had gotten so bad, that I had grown fearful of damaging circuits I was powering it with.  The capacitor-swap was the first thing I tried, and that proved to have zero effect.  I was chuffed to discover, on rummaging around my boxes of components, the bag of pots I had ordered.  Long story short, the potentiometers proved to have been the culprits!  Once replaced, both supplies returned to being fluctuation-free - RESULT!

    Wee!